Copper base alloy



Patented Jan. i4, 135

ATES

COPPEI} BASE ALLOY Elmer L. Munson, Naugatuck, Conn., assignor to TheAmerican Brass Company, Waterbury,

60mm, a corporation of Connecticut No Drawing. Application October 20,1934, Serial No. 749,276

L. Claims.

This invention relates to a copper base alloy containing copper, nickel,aluminum and beryllium.

It is one object of the invention to provide- 5 a copper base alloy thathas a combination of hardness, strength, ductility and a wide heattreating temperature range not found in other copper base alloys.

The foregoing and other objects will appear 10 from the followingdescriptionancl appended claims.

Several copper base alloys now in commercial use may be hardened andstrengthened by the heat treating process known as precipitation or agehardening treatment. Of these alloys two most important are thecopper-nickel-aluminum alloy and the copper-nickel-beryllium alloy of Ithe following approximate compositions:

Per cent Per cent Copper 94.0 Copper 97.25 Nickel 5.0 Nickel 0.50Aluminum 1.0 Beryllium 2.25

Alloys of the above and similar compositions have certain objectionablecharacteristics which discovered. For example, the copper-nickelaluminumalloy cannot be satisfactorily hardened at temperatures below about 325(3., while my new alloy can be heat treated at temperatures as low as250 C. and consequently at less expense. Again thecopper-ruckel-beryllium alloys have a heat treating temperature rangeextending from about 250 C. to about 325 C. which is a rather narrowrange for use by the 35 fabricating trade and is a source of troublewhen the heat treating time and (or) temperature is not closelyregulated. The hardness and several other mechanical property values ofthe copper-nickel-beryllium alloys reach a peak 40 somewhere in theneighborhood of 300 0., de-

pending up'on the amount of cold working and time of heating. If theapplied heat is materially below 250 C. or materially above 325 C., thehardness and other characteristics are not 45 satisfactory forcommercial usage. In other words in the heat treatment of the abovedescribed copper-nickel-aluminum alloys and copper-nickel-berylliumalloys the temperature must be closely regulated with respect to theselected 50 temperature, and similarly the time must be closely defined.My new alloy does not require such close regulation of the heattreatment because variations of fifty degrees within the heat treatingtemperature range do not seriously in- 55 fluence the hardness and othermechanical properties. In other words, there is a gradual increase inthe mechanical property values from about 250 C. to about 550 C. About550 0., the mechanical property values drop on? until a temperature ofabout 800 C. is reached, where do not appear in the new alloy which Ihave the metal, after quenching, is suiliciently soft to readily permitof cold working.

Many of the copper rich quaternary alloys 01 copper, nickel, aluminumand beryllium have no properties which make them'any better than the 5more simple binary or ternary alloys, butl have discovered a narrowrange of composition in which these alloys possess the desirablecharacteristics of the previously known alloys of these metals andwhich, in addition, are free 10 from several undesirable features.

The most valuable composition range is approximately Copper 913.75 to96.75 15 Nickel 2.0 to 5.0 Aluminum 0.5 to 2.0 Beryllium 0.75 to 1.25

When the percentages of nickel, aluminum v and (or) beryllium materiallyexceed the maxi- 20 mum limits of these narrow ranges the alloy cannotbe fabricated into sheets, wire, rods, and tubes by the usual coldworking methods such as rolling and drawing.

If the nickel, aluminum and (or) beryllium contents are materially lowerthan the minimum limit, the resulting alloy can be cold workedcommercially into wrought forms but will not develop the advantageoushardness, strength and ductility characteristic of the alloys within thespecified limits.

However, when only the beryllium content is lowered, my new alloy stillshows better mechanical properties than the previously mentionedcommercial copper-nickel-aluminum alloy. A composition such asapproximately Copper 90.25 to 97.25 Nickel 2.0 to no Aluminum 0.5 to 2.0Beryllium 0.25 to one is of value for certain purposes.

A. preferred specific alloy for tensile strength, hardness and ductilityis one comprising approximately 94.5% copper, 3.5% nickel, 1.0%

aluminum, and 1.0% beryllium.

A useful alloy which can be produced at more I moderate cost is onecomprising approximately 95% copper, 3.5% nickel, 1.0% aluminum and 0.5%beryllium.

In the manufacture of my new copper base alloy the aluminum andberyllium may be added to the nickel and copper in the form of anaddition alloy, such for example as one containing beryllium andaluminum in the proper proportions or as alloys of beryllium and/oraluminum with copper. The alloy is cast in chill or other molds and theingots or shells may be hot and (or) cold rolled or drawn to the desiredsize and shape.

The cast ingots or shells 00 can also be extruded or forged, if desired.It, at any stage, it is desired to soften the alloys for workingpurposes,this may beaccomplished by heating preferably to about 800 C.(although a certain degree of softening will occur at any othertemperature between approximately 550 C. and themelting point), and thenrapidly cooling, preferably by an immediate quench If so desired, thenew alloy can be hardened automatically while in commercial service ifthe operating temperature is within the wide temperature rangeaforementioned.

My experiments have indicated that the nickel content should exceed thesum total of the aluminum plus beryllium content to secure the maximumhardness and strength.

An important advantage of an alloy made in accordance with the presentinvention is that the amount of beryllium required is only aboutone-half the quantity necessary in the prior copper-nickel-berylliumalloy to obtain nearly as great hardness and tensile strength values. Atthe present time, beryllium metal is more or less rare and expensive.tion in beryllium content means that the base metal cost of the newalloy will be about 60 percent less than that of the prior alloy atcurrent metal prices. This reduction is reflected in a lower sales pricefor the new alloy and consequently permits more extensive use of same infields heretofore considered prohibitive due to the high cost of theprior copper-nickelberyllium alloy.

Another'advantage of an alloy made in accordanc'ewith the presentinvention is the greater softness of the annealed material in comparisonwith that, of the copper-nickelberyllium alloy. For example, theRockwell hardness of my new wrought alloy after annealing at 800 C. for/2 hour followed by a quench in water is about G 12, while the Rockwellhardness of the copper-nickel beryllium alloy similarly annealed andquenched is about G 25. This increased softness of my newcopper-nickel-aluminum-beryllium alloy will permit greater reductionsbetween anneals and with somewhat less die wear when drawn into wire ortubes than is possible with the copper-nickelberyllium alloys.

Another advantage embodied in my invention is that afiorded during thecasting operation by the presence of the protective aluminum film on thesurface of the molten metal which helps to prevent the lossof valuableberyllium by volatilization. In the copper-nickeL-beryllium alloy someloss of the expensive element beryllium occurs by volatilizationwhen themetal is I alloys containing nickel and aluminum make my Therefore, thisreduc- -1.25% beryllium, and the balance copper, in

new alloy particularly suitable for such articles as non-sparking tools,hardware, knives,

'chisels, springs, wire screens, tubes, gears, terminals, clips, bolts,nuts, coins, clock parts; jewelry, chains, valves, hinges and many.other articles. 5

Having thus set forth the nature of my invention, what I claim is:

1. An alloy composed of copper. nickel. aluminum and beryllium inproportions substantially -within the following ranges: 10

Percent Copper 91.75 to 96.75 Nickel 2.0 to 5.0 Aluminum 0.5 to 2.0Beryllium 0.75 to 1.25 15 2. An alloy comprising approximately 94.5%copper, 3.5% nickel, 1.0% aluminum and 1.0%. beryllium.

3. A copper base alloy comprising approximatelycopper, 3.5% nickel, 1.0%aluminum and 0.5% beryllium.

4. A copper base alloy composed of copper, nickel, aluminum andberylliumin proportions substantially within the following ranges:

25 Percent Copper 90.25 to 97.25 Nickel --a 2.0 to 7.0 Aluminum 0.5. to2.0 Beryllium 0.25to 0.75 30 5. A copper base alloy which is capable ofextensive drawing, rolling and other forms of hot and cold workingcomposed of 2.0% to 7.0% nickel; 0.5 to 2.0% aluminum; 0.25 to 1.25%beryllium, and the balance substantially copper.

6. A copper base alloy which has been hardened by heat treatmentcomposed of 2.0% to 7.0% nickel; 0.5 to 2.0% aluminum; 0.25 to 1.25%beryllium, and the balance substantially copper, in which the nickelcontent exceeds the aluminum and beryllium content.

7. A copper base alloy characterized bybeing hardenable by heattreatment composed of 2.0% to 7% nickel; 0.5 to 2.0% aluminum; 0.25 to45 which the nickel content is approximately in the ratio of 3 to'laluminum and approximately 0.25 to 1.25% of beryllium, the balance ofthe 60 alloy consisting of copper, and the nickel content being about 3times the aluminum content, to heat treatment involving heating thealloy to a temperature of the order of 800 C. followed by rapid coolingand reheating to a. 65 temperature of about 250-550 C.

10. A manufacture as set forth in claim 9, in which the alloy, afterrapid cooling from the temperature of the order of 800 C. is subjectedto cold working prior to reheating.

' EL'MER L. MUNSON.

